2118567981 has 4 divisors (see below), whose sum is σ = 2824757312. Its totient is φ = 1412378652.

The previous prime is 2118567959. The next prime is 2118567991. The reversal of 2118567981 is 1897658112.

It is a happy number.

2118567981 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2118567981 - 2⁶ = 2118567917 is a prime.

It is a super-2 number, since 2×2118567981² = 8976660580236832722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2118567981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2118567991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 353094661 + ... + 353094666.

It is an arithmetic number, because the mean of its divisors is an integer number (706189328).

Almost surely, 2^2118567981 is an apocalyptic number.

It is an amenable number.

2118567981 is a deficient number, since it is larger than the sum of its proper divisors (706189331).

2118567981 is an equidigital number, since it uses as much as digits as its factorization.

2118567981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706189330.

The product of its digits is 241920, while the sum is 48.

The square root of 2118567981 is about 46027.9043733255. The cubic root of 2118567981 is about 1284.3423446141.

The spelling of 2118567981 in words is "two billion, one hundred eighteen million, five hundred sixty-seven thousand, nine hundred eighty-one".